A sweep auger of the general type, to which the present invention is applicable, is described in detail in U.S. Pat. No. 3,563,399, granted Feb. 16, 1971, for "Method For Circulating Grain Stored In A Circular Bin", wherein the patentee is the inventor of the present invention. In such patent there is described an apparatus for removing a horizontal layer of grain of uniform thickness from the bin floor during each complete revolution of the auger across the bin floor and which apparatus received immediate commercial success and is now presently widely used.
It has been found in the field that broader demands were being made for the invention of U.S. Pat. No. 3,563,399 whereby users of the equipment desired applicant's apparatus to move products of different particle size. Relatively large particle products, such as coffee beans, for example, cannot be removed in a uniform layer from the bin floor when the auger has flights of relatively small diameter at the outer end thereof, such as illustrated for the sweep auger in U.S. Pat. No. 3,563,399.